1. Field of the Invention
The present invention relates to an image processing apparatus.
2. Description of the Related Art
Image processing apparatuses have functions of decoding a scan image compressed by a joint photographic experts group (JPEG) codec, and displaying on its operation panel the thumbnail thereof and a preview image of the thumbnail specified by a user. With this function, the preview image can be partially cut out or enlarged to check the outline of the scan image. The decoded image data is stored in a work area of a memory for processing and editing the preview image. This requires all code data to be decoded to display an image. The code data is compressed by the JPEG codec, and thus image processing is complicated. Consequently, it takes time to wait for image display, and a work area with a large capacity is required to store image data.
For example, Japanese Patent No. 3719251 discloses a conventional technology in which, to transmit code data by email, the code data is encoded by scalable encoding, i.e., JPEG2000 encoding, so that a plurality of pages of subcode data is transmitted. Japanese Patent Application Laid-open No. 2004-088425 discloses another conventional technology in which, in process of editing code data, only the header is changed while other content and data are left unchanged. This enables decoding for reproduction at a resolution level different from that of an original image.
However, in the former conventional technology, because the technique is practiced by emails, the subcode data is extracted on a server side, which is the main unit of the image processing apparatus, and therefore a processing time is required. In the latter conventional technology, when the subcode data is selected and extracted, editing is performed in an encoded state. Because it is also the processing on a copier, a processing time is required.